A genome is an organism's hereditary information—its DNA—and Biologists have been studying them since the early 20th century. Genome sizes vary a lot, and the numbers can be very surprising. To wit, the record for largest genome goes to ... a plant! A rare flowering plant called Paris japonica has a genome 50 time longer than that of humans, and the longest known genome of any organism.
Here are a selection of extraordinary Christmas trees throughout the world—most are local traditions, many are breaking records, and one appears to break through a suburban roof.